2018湖南多校第八场 训练日志

#include <cstdio>
#include <iostream>
#include <set>
using namespace std;
#define ll long long

template<class T>
inline void read(T &ret){
    int sign = 1;
    ret=0;
    char c = getchar();
    while(c!=‘-‘ && (c>‘9‘||c<‘0‘))c=getchar();
    if(c==‘-‘)sign=-1;
    else ret = c-‘0‘;
    while(c=getchar(),c>=‘0‘&&c<=‘9‘){
        ret = ret*10+c-‘0‘;
    }
    ret*=sign;
}

int n;

struct node{
    ll x,y,z,t;
    node(ll x=0,ll y=0,ll z=0,ll t=0):x(x),y(y),z(z),t(t){}
    friend bool operator < (node a,node b){
        if(a.x==b.x){
            if(a.y==b.y){
                if(a.z==b.z){
                    return a.t<b.t;
                }return a.z<b.z;
            }return a.y<b.y;
        }return a.x<b.x;
    }

    friend bool operator == (node a,node b){
        if(a.x==b.x&&a.y==b.y&&a.z==b.z&&a.t==b.t)return 1;
        return 0;
    }
}p[10000007];

multiset<node> st;

node findnode(node a,node b){
    ll xx = b.x*2-a.x;
    ll yy = b.y*2-a.y;
    ll zz = b.z*2-a.z;
    ll tt = b.t*2-a.t;
    return node(xx,yy,zz,tt);
}

int main(){
    while(scanf("%d",&n)!=EOF){
        ll sumx=0,sumy=0,sumz=0,sumt=0;
        for(int i=1;i<=n;i++){
                scanf("%lld %lld %lld %lld",&p[i].x,&p[i].y,&p[i].z,&p[i].t);
            //read(p[i].x);read(p[i].y);
            //read(p[i].z);read(p[i].t);
            sumx+=p[i].x;
            sumy+=p[i].y;
            sumz+=p[i].z;
            sumt+=p[i].t;
        }
        st.clear();
        node zx = node(sumx,sumy,sumz,sumt);
        for(int i=1;i<=n;i++){
            p[i].x*=n;p[i].y*=n;
            p[i].z*=n;p[i].t*=n;
            st.insert(p[i]);
        }
        int ans=1;
        for(int i=1;i<=n;i++){
            node dc = findnode(p[i],zx);
            //cout<<st.count(dc)<<" "<<st.count(p[i])<<endl;
            if(st.count(dc)==0){

                ans=0;break;
            }
        }
        if(ans)puts("exist");
        else puts("not exist");
    }
    return 0;
}